The Man in Black
by abosdbfa
Summary: A man in black attacks the tenth Vongola boss when he is at his most vulnerable state. In the wake of Tsuna's death, Reborn vows to find this man and avenge his fallen student.


**AN: Hi, abosdbfa here. This here if you didn't already know is a KHR and Fate Zero crossover. It's set in the KHR world but has Fate characters in it meaning there is no Holy Grail war in this fanfiction. Think of it like a parallel world where it's the same people but with different roles. Perhaps Saber is a prestige Mafia boss or Kotomine as a Hit man in this world, he was a mercenary in the original Fate. Find out on this story. **

Chapter 1 Pilot

Brown eyes stare at the empty room before him as he sat alone in his chair doing the usual paper work.

It's been 10 years since he's been announced as the next in line of being the Vongola boss and right now, times have been tough.

With the amount of enemies Vongola has with other mob bosses, his guardians have been busy as of late but their busyness isn't particularly the reason why he's alone. His guardians have been avoiding him personally as much as possible ever since the incident involving laying waste to an entire family in his own hands.

Gokudera as well as Yamamoto were shocked that he was able to unleash such carnage upon actual people.

HIbari and Mukuro remained silent for the rest of that night not really knowing what to say.

Ryohei tried to look away not even wanting to make direct contact with his boss.

Chrome … pure and innocent Chrome was shaking in fear, at him no less.

The man was glad that Lambo wasn't there for that mission but once he heard the stories, the usual lazy cow suddenly had a full schedule.

He couldn't blame them after seeing such a gruesome sight but he had no other choice. It was either his own familia or the enemy.

_-Flashback-_

"_Alright here's the plan. The Asaro family has been conducting experiments on orphan children and it must be put to a stop. I promised Primo I would destroy any mafia bosses that commits such sins or atrocities. Mukuro I know this hits harder on you than anyone else but keep a level head." Tsuna ordered._

"_Kufufu … such things are behind me Vongola. Although it'll be all the more pleasant to put them in their place." Mukuro stated._

"_Judaime! Are you sure we can trust him with this mission? I think he should sit this one out in case he does anything funny and mess up this mission." Gokudera said as he still didn't fully trust anyone but himself to help his dear boss, especially Mukuro._

"_We're going to need his illusions for this one Gokudera so he's a vital part of this mission." Tsuna said._

"_We can bring Chrome if we need illusions." Gokudera reasoned._

"_Chrome has a time limit with her illusions and I would feel more assured if Mukuro was there with her in case something goes bad." _

"_I … I see but if that's your decision Judaime than I will follow it absolutely."_

_Man I'd rather be teamed up with that cow than Mukuro. Gokudera mentally complained._

"_Maa maa Gokudera, Tsuna does have point. Mukuro's illusions have saved us plenty of times before so you shouldn't be so uptight with him all the time." Yamamoto said before Gokudera started having a one-sided argument with him making the Vongola boss sigh in slight annoyance._

"_Anyway, the enemy knows that were coming and based on our past records, we've been known to handle big missions such as this one as a team and that's what they're going to expect." Tsuna said._

"_So we divide and conquer to the EXTREME!" Ryohei said with excitement._

"_Not exactly. We do what we always do and go in there as a team like always." _

"_But wouldn't that be falling right into their hands?" Chrome asked._

"_No, you, my guardians, are going to flank from the front and attack with all that you have. Mukuro, you and Chrome will be in charge of making a copy of me fighting alongside you and with all the attention up front …." Tsuna began._

"_Less attention on the back." Gokudera finished._

"_The layout of their HQ is a large mansion similar to ours. Their boss should be in the second floor and that's where I'll attack. The rest of you handle the first floor and draw attention to yourselves. Gokudera, Hibari, you're in charge of handling the front lines. You'll be the first ones to strike. Yamamoto, you're in charge of finding the children and setting them free. Ryohei, there's no telling what they did to those kids so you'll be going with Yamamoto in case they're injured. Chrome and Mukuro, remember that they must think that I'm with you guys so make your illusion of me is as realistic as possible and give support to Gokudera and Hibari in case they need it." Tsuna said as all his guardians nodded at their leader's orders._

"_Boss … are you sure you're not going to need any help when you attack the Asaro's family boss? He's sure to have guards with him to help him." Chrome said worried._

_Tsuna just smiled at her affectionately and reassured her that he'll be fine and that she should be more worried about herself than him. _

"_Don't get in my way herbivore." Hibari addressed to Gokudera._

"_Right back at you Skylark." Gokudera said._

"_Extreme!" Ryohei screamed._

"_You have your orders. Stick to the plan and meet up on the second floor once your task is complete." Tsuna said._

"_Understood!" They all exclaimed._

_-Time skip-_

"_So far so good." Tsuna said as he stood floating in the air a few meters away from the mansion hidden within a forest of trees._

_The plan was going smoothly as all hell broke loose once Hibari and Gokudera stormed into the mansion with Chrome and Mukuro as well as an illusion of himself were working as support and attacking from a range. Once the coast was clear, Yamamoto and Ryohei went in search of the orphan kids starting at the basement._

"_Trace on." Tsuna said as he was now able to see through the walls of the mansion and see the highlights of people now as skeletons, heading towards the first floor and intercept his guardians. Thanks to his updated contacts that Spanner and Shoichi so kindly upgraded, he is now able to see through walls as well as see in night vision. Infrared, and as always operation x mode all with a simple voice command._

_There was still a dozen people in the second floor but not too much he can handle and with that, Tsuna now blazed his way towards the balcony of the mansion as he made his entrance known as he was now face to face with the Asaro's family boss as well as a few dozen of his body guards. _

_They were all shocked to see the Vongola boss in front of them while at the same time, attacking his cronies. _

"_I see … very clever Vongola but I'm glad that you're here." Asaro said as he leered at Tsuna with distaste._

"_It's over Asaro! Turn yourself in to the Vendice and I'll let you and the rest of your friends go." _

"_You think I want to spend the rest of my life in prison?" _

"_Bad people should be locked up in bad places." _

"_Hmph, you have no leverage over me."_

"_If I'm not mistaken, your entire family is losing to my 6 guardians so yes, I do think I have the upper hand here." Tsuna smirked._

"_Oh that's where you're wrong. I knew that you were going to catch me eventually because of my bad deeds with the orphaned children. Honestly I don't see what I'm doing wrong here. Nobody wanted them in the first place." Asaro smiled sadistically._

"_That gives you no right to just take them and do with them as you please!" Tsuna yelled._

"_And just what exactly did you think I did with them?" Asaro asked as he turned towards the cameras as it was showing all his guardians escorting the kids out of their prisons._

"_You didn't?!" Tsuna exclaimed in shock._

"_Their ticking time bombs infected with a deadly virus inside each child. Anyone within the immediate area of these kids will get infected and will suffer a fate worse than death and all I have to do is push this button." Asaro said sadistically as he stared the defeated form of Tsuna. _

"_What do you want?" Tsuna asked with barely restrained malice._

"_I want you to get on your knees and beg for forgiveness and just maybe, I'll let them go free. You'll let me and the rest of my family go and give me the funds to start anew." Asaro demanded._

"_You son of a …!" Tsuna screamed._

"_Ah ah ah, one wrong move and it's not just your guardians that will be dead but all 352 children will go with them." _

_Tsuna just gritted his teeth before getting on his knees and bowed before the Asaro's family boss._

"_Please … have mercy." Tsuna said bowing his head, his bangs hiding his eyes to not give him the satisfaction of seeing him in frustration._

_Asaro and his men all laughed at the defeated form of the great Vongola boss._

"_You know what … forget the deal. Seeing you, the great and mighty Vongola Decimo in despair might give me better satisfaction than starting anew. It'll only be a matter of time until the Vendice get involved anyway." Asaro said as Tsuna looked up at him in shock._

_Time seemed to slow down and something within Tsuna's mind snapped as all moral codes he had with never taking a life was thrown out the window. Tsuna always took the much more difficult path if it meant not taking a life, especially if it meant one of his friend's life. He may have ended Byakuran's but seeing that he had no choice in the matter, he was quickly forgiven. Not to mention the fact that he's still alive and well in his timeline so it was as if it never happened. _

_Within a fraction of a second, Tsuna was now in front of Asaro with his hand right in his face. _

"_X-burner." Tsuna softly spoke as his hand ignited and completely disintegrated Asaro's face off with the body releasing the remote control of the detonator as it softly landed on the ground. _

_The body guards all stared in shock before all of them started scrambling to reach for the button in an attempt to get a leverage over the Vongola boss so that they wouldn't meet the same fate only for them to realize too late that it would have the opposite effect._

_Tsuna, in all his rage sped towards each body and completely tore the limbs off of them as he increased his own physical strength as well as the heat of his flames now being hot enough to completely melt flesh to the bone as to make sure his family as well as 352 children are kept safe. _

_Tsuna screamed as he continued to slaughter the rest of Asaro's men and each time he killed one, he lunged for another and scream again. _

_To the untrained ear, Tsuna's own scream was that of a broken man filled with corrupted determination as he continued to feel the shame and guilt of ending a life and it pierced right through his heart and his very soul. The overwhelming pain almost overtaking him as if he was one of the victims as he continued to scream in pain. _

_There was only one man left and he held the controller._

"_Stand back! I mean it! Any closer and you're friends are dead!" The man spoke as there was a shaky hold on the controller with his eyes conveying absolute terror as Tsuna was covered in the blood of his comrades._

_Using the same method as he did with their boss, Tsuna disintegrated the man's face as he sunk to the floor with a splat. _

_Tsuna reached for the controller and crushed it. As soon as he turned around, he was sick to his stomach and he wanted nothing more than to just cry, cry like he always did 10 years back. Be the same Dame-Tsuna that cries and complains too much._

_Right when he was about to lose strength and pass out …._

"_Judaime!" Gokudera screamed excitingly opening the door to the main room of the second floor before he saw what laid in front of him. _

_It didn't take long before the others showed up and looked at the messy room in red. _

"_Tsuna … what did you …? Yamamoto couldn't finish as he continued to look at the dead corpses in shock._

_Mukoro and even Hibari looked around a bit disgusted with all the severally burnt bodies and melted flesh. You couldn't tell which limb belonged to each body as it was scattered everywhere across the room. _

_I didn't even take it that far with my victims. Mukoro thought._

_Between burning alive and getting stabbed, most people would prefer the latter._

"_Boss … what happened?" Chrome shakily looked at body to body not to mention her own boss was covered in blood._

"_I … I …." Tsuna didn't have an answer as everything only sounded like an excuse for him, an excuse to have the right to murder. Having nothing to say for the matter he opted to change the subject, something that he desperately wanted to do._

"_Are you guys alright?" The question being asked with voice small and monotone._

_A few of his guardians nodded their heads while others just looked away, something he took note of and gave an exhausted sigh._

"_If everyone is alright … mission success. Let's go home guys." Tsuna said before they silently followed him and their very silence was suffocating. _

_-End flashback-_

The children were cured of their disease as it was slowly but surely removed from their system.

The guardians were glad they were able to reach them in time to save them but none questioned or even bothered to confront with their boss on the matter of the viral disease.

These days, the only time he got to see his friends was when they announce what mission they are going to take and when they will be back and at most cases, the would avoid eye contact with as much as humanly possible.

When Tsuna was finally ready to explain himself, things didn't go the way that he planned.

_-Flashback-_

"_J-Judaime … we're all here." Gokudera said as all of his Guardians were present in his office all seated in comfortable chair. Some fidgeted in their seat while other remained impassive. _

_There was moment of silence before Tsuna cleared his throat and spoke with clarity to make sure his Guardians understood what he was trying to say unlike the last time he tried to explain himself._

"_You've been quite distant with me as of late … why are you acting like this?"Tsuna asked already knowing the answer._

"_What do you mean Tsuna?"Yamamoto asked avoiding eye contact with him as much as possible._

"_LIKE THAT!"Tsuna screamed as he swiped all the object off his desk in frustration which made all the guardians flinch from the ice in his tone._

"_Please don't be angry boss, calm down. All of us have been busy with mission, that's all." Chrome said silently. _

"_Really, then when was the last time ANY of us had a real conversation?" Tsuna asked which everyone remained silent._

"_There's something you're not telling me and I want to know what that is." Tsuna demanded._

"_Exactly what do you want us to say, Sawada?" Hibari crosses his arms. Tsuna noted that he didn't call him herbivore like he usually did as he started to grip his hair in frustration._

"_I've stated my question loud and clear, don't make me repeat myself." Tsuna said impatiently. _

_Why are they being so dishonest? Just how long have we been friends? Is our friendship so shallow that they would actually give into their fear of me rather than their trust? Tsuna thought feeling completely stressed. _

"_Judaime, we're not avoiding you, we're just … just …. Gokudera couldn't finish._

"_You're lying." Tsuna said as everyone looked away._

_"You're just trying to distance yourself is that it? That sounds pretty much the same to me." Tsuna said his voice sounding a bit strained. He wanted to scream at them with all his might. _

_Why don't they just tell him? Are they afraid that they would hurt him? Well, they don't have to worry about that, because they already did._

_"Boss… we're sorry." Chrome suddenly spoke up_

_"Oh so now you're apologizing? So does that mean, I was right?" Tsuna said trying to hold back his sarcasm_

_"Kufufu… Sawada Tsunayoshi… I would strongly advise you not to use that kind of tone on my precious Chrome." A murderous aura surrounded Mukuro. Usually this would scare Tsuna, but right now, the boss couldn't care less if he was murdered on the spot right now, he just wanted to get to the point._

_"And I would like to advise you to tell me the truth or else!" Tsuna returned the glare as well as his own murderous aura._

_"What do you want us to EXTREMELY say?" Ryohei asked while others also started murmuring the same questions._

_Tsuna felt his anger rise_

_"Damn it!" He slams the table everyone immediately went silent._

_"JUST SAY IT!" Tsuna roared as he tightly shut his eyes almost close to tears_

_"SAY HOW YOU DAMN FELT WHEN YOU SAW ME MURDER SOMEONE!"_

_"We got scared of course!" Lambo suddenly yells. Everyone turned their attention to the cow child, surprise that he suddenly spoke when he was silent all this time._

_Tsuna stares at his youngest guardian in a bit of shock._

"_I snuck into the mission. I didn't actually participate but I saw from afar what you did."_

_The others then noticed there was no other way they could take back what Lambo said, so…_

_"Tsuna… why? Why did you kill?" Yamamoto drops his mask looking at Tsuna _

_"I thought you weren't that kind of person who'd ever take a life."_

_Tsuna's eyes widen slightly but he remained a stoic… listening to what they had to say._

_"Juudaime, you… you said you can never take a life… but now…" Gokudera shut his eyes, as if thinking this wasn't real._

_"You EXTREMELY kill people like they have no significance in this world. There were body parts everywhere!" Ryohei said looking at Tsuna, shaking his head slightly_

_"Kufufu… I actually have no problem with what you did, but my opinion of you has drastically changed… you're no different from anybody else." Mukuro said shrugging a bit_

_"Everytime I see Boss… I can't help but remember when you were covered in… in… blood." Chrome said softly looking down with fear evident in her eyes._

_Hibari suddenly smirks "You've grown into a fearful person… Sawada. You are no herbivore."_

_Fearful person? More like a monster! Tsuna thought as he clenches his fists. He sighs with his eyebrows furrowed. _

_This was what he wanted right? To know what they were thinking of him and how they felt. And now he knew that not only were they scared but also disappointed, disappointed that he had done such a thing._

_He felt ashamed. He looked at each of their expressions. Lambo was looking at him fearfully with eyes full of tears. Chrome, Yamamoto, Gokudera and Ryohei were looking at him before looking away. And then Hibari and Mukuro were just giving him a blunt look._

_He opens his mouth, wanting to say he did such things because he wanted to protect them. They didn't know about the virus acting as bombs and how he had no choice but… to him, it still sounded like an excuse._

_So it might sound like one in their ears as well._

_"Are… are you satisfied now?" Lambo suddenly said_

_Tsuna shut his eyes _

_"Dismissed"_

_And just like that everyone left without saying a word._

_-End of Flashback-_

Tsuna sighed to himself as he massaged his temples. He finished the last of his paper work before standing up and stretching out his limbs.

It's been months since that incident and his Guardians are more or less giving him the cold shoulder. At least it didn't affect Vongola as a whole. They still did their duties vigilantly aw who cares now.

"I wish … I could just get away from it all. From everyone, from everything. Being Vongola boss, from work, from my friends, my Guardians. I WANT MY LIFE BACK! I WANT TO LIVE MY OWN LIFE … not just be thrown and trained to another." Tsuna said as he slumped down his chair.

Tsuna's Hyper intuition was in full gear as he jumped off his chair and landed on the other side of the room as a rocket shell exploded, destroying the window of his office as it left a giant gaping hole.

"As expected of Vongola Decimo." A mysterious voice said.

It was then a man dressed in black entered through the hole and glared at Tsuna.

"Who are you and what do you want? Tsuna asked.

"I'm here to grant you your wish. To live your own life. Too bad it's going to have to be the next one." The man said as he pulled out a giant strange looking pistol.

Tsuna entered hyper dying will mode and initiated Operation X.

"I was hired to take you out."

"X-…!" Tsuna said as the man pulled the trigger.

-Meanwhile-

All the Guardians managed to finish their mission at the same time as they all traveled the same road together as they made their way home.

Right when they were about to reach the Vongola Mansion, a loud explosion was heard. All of them rushed towards the seen and were horrified to see that the Mansion was in flames.

There was another explosion in the mix at the second floor of the mansion, Tsuna's office.

Yamamoto used his boxes and summoned Jiro and Kojiro to make it rain and to try and take out the flames.

Gokudera rushed inside the burning building praying to god that his boss was alright.

Ryohei followed close behind to help any stragglers that's inside the mansion.

"Judaime! Judaime where are you?!" Gokudera screamed.

He was in front of the door of the main office of the Vongola boss when he tried to knock and scream if Tsuna was alright, he didn't get an answer.

Gokudera kicked down the door and right when he entered, he saw a man in black holding the Vongola Ring as if it was some kind of trophy.

"Bastared!" Gokudera screamed as he pulled out G's bow and arrow and shot towards the man in black. The man easily dodged before pulling out a large strange looking pistol and opened fire in which Gokudera was able to dodge by ducking, hiding behind cover. Right when he was about make a counter attack, the man was gone.

He looked around for Tsuna only to get sick in his stomach as there was only a burnt corpse with Tsuna's flame retardant clothes with a giant golden bullet lodged in his head. He carried the corpse and rushed outside. The moment he got outside, he dropped the corpse, got on his knees and started bawling his eyes out, screaming how much of a failure of a right hand man he was.

When the others wondered what Gokudera was crying about, they know whose corpse that was and they hung their head low with shame.

All the Guardians felt a giant murderous aura. Gokudera in his rage thinking it was the man in black, prepared his arrows only to realize who it was that was giving them such an intense and suffocating aura.

"What the hell happened while I was gone?!" Reborn screamed pulling out Leon as it morphed into a green gun ready to fire at any given moment.

**AN: Before anyone points fingers, yes the inspiration behind the sudden distance between Tsuna and his Guardians comes from the story Their Boss. Only unlike that story, it appears the main character has been killed by another character from Fate and in the first chapter no less. I'm sure you know who it is since who else uses fucking guns in a show about magic. Reborn is pissed and he seems to be out for blood. The notorious free-lancer vs. the legendary hit-man. What's going to happen next, find out in the next chapter of The Man in Black. **

**P.S. This is my third story meaning my uncompleted first story is top priority. If this gets enough reviews might make a second chapter. Best wishes to this story. Please Review. **


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